Device for mounting a negative plate on a printing cylinder



' United States Patent lnventor Appl. No.

Filed Patented Assignee Priority Louis G. Corse Paris, France 797,881

Feb. 10, 1969 Nov. 17, 1970 Societe D'Etudes De Machines Speciales,Societe Anonyme Paris, France Feb. 14, 1968 France DEVICE FOR MOUNTING ANEGATIVE PLATE 0N A PRINTING CYLINDER 3 Claims, 5 Drawing Figs.

U.S.Cl. 101/415-1 Int. Cl. B41f27/06, B4lf27/l2 Field oi'Search10l/4l5-l. I

378, 125, 126, 131, 13l.5, 132, l32.5, I33; 346/138;5l/364,365,367

[56] References Cited UNITED STATES PATENTS 1,545,791 7/1925 Owenl01/4l5.l 1,881,075 l0/l932 Gutmann l0l/4l5.l 2,194,424 3/1940 Grupel0l/4l5.l

Primary Examiner-Robert E. Pulfrey Assistant ExaminerJ. Reed FisherAttorney-Irving M. Weiner ABSTRACT: A device for mounting a negativeplate or sheet on a printing cylinder, of which the outer peripheralwall is discontinued in order to provide a longitudinal apertureextending throughout the length of the cylinder, comprising acylindrical tensioning sector fitting in said aperture and forming withits peripheral surface the partial continuation of the cylinderperipheral surface, characterized in that it comprises in saidlongitudinal aperture of the cylinder at least one cylindrical bearingsector adjacent to said tensioning cylindrical sector, the outer surfaceof said cylindrical bearing sector completing the outer peripheralsurface of said cylinder and tensioning sector, and being mounted fortransverse adjustment on the pair of lateral flanges of said cylinder.

Patented Nov. 17, 1970 3,540,376

Sheet 1 org Patented Nov. 17, 1970 3,543,376

Sheet 2 of 2 {/3 1 51214, &

DEVICE FOR MOUNTING A NEGATIVE PLATE ON A PRINTING CYLINDER BACKGROUNDOF THE INVENTION The present invention relates to devices for mounting anegative plate or sheet on a printing cylinder.

Various devices have already been proposed for tensioning and fasteninga negative plate or sheet to a printing cylinder. A known deviceconsists of a locking key or bar engageable in a longitudinal slotformed in the wall of the printing cylinder and retaining in this slotthe bent or flanged marginal portions of the plate. Another tensioningand fastening device utilizes jaws to which the edges of the negativeplate are secured, these jaws being subsequently moved towards eachother for tensioning the negative plate.

However, all hitherto known devices are objectionable in that they giverise, on the surface of the printing cylinder. to empty gaps ofrelatively substantial width, constituting as many areas that cannot beutilized for printing purposes.

SUMMARY OF THE INVENTION It is the essential object of this invention toobviate this inconvenience by providing a particularly simple devicecapable of minimizing the width of these useless gaps.

To this end, the device according to the present invention for mountinga negative plate or sheet on a printing cylinder,

' of which the outer peripheral wall is discontinued in order to providea longitudinal aperture extending throughout the length of the cylinder,comprises a cylindrical tensioning sector fitting in said aperture andforming with its peripheral surface the partial continuation of thecylinder peripheral surface, the negative plate or sheet having one endbent and anchored to one edge of said sector and its opposite end alsobent and anchored to the registering edge of the cylinder aperture, asupport for said tensioning sector which is rotatably mounted about thecylinder axis, and means for adjusting the angular position of saidsupport of said tensioning sector in relation to said cylinder forcontrolling the tension of said negative plate on the cylinder, and ischaracterized in that it comprises in said longitudinal aperture of thecylinder at least one cylindrical bearing sector adjacent to saidtensioning cylindrical sector, the outer surface of said cylindricalbearing sector completing the outer peripheral surface of said cylinderand tensioning sector, and being mounted for transverse adjustment onthe pair of lateral flanges of said cylinder.

The mounting device according to this invention is advantageous in thatthe width of the longitudinal gaps existing between the cylindricalbearing sector or sectors, the tensioning sector and the longitudinaledges of the continuous cylinder wall can be reduced to a very smallvalue while permitting, due to the transverse shifting of thecylindrical bearing sector or sectors, of introducing the bent or foldededges of the negative plate into the gap left to this end between thecylindrical tensioning sector and the adjacent longitudinal edge of thecylinder wall.

In fact, the empty gap or interval necessarily provided for introducingthe bent edges of the negative plate or sheet into the cylinder fortensioning this negative plate or sheet is divided into a.plurality ofelementary narrower gaps. Another advantageous feature characterizingthis arrangement is obtained when the negative plate or sheet isintended for making several successive prints during each singlerevolution of the printing cylinder, for example for printing labels,illustrations, vignettes, etc., separated by nonprinted areas. In thiscase, the very reduced width of the empty or blank gaps left on theperiphery of the printing cylinder may be inferior to the distancebetween two adjacent or successive prints, so that no circumferentialspace is lost during the printing process.

BRIEF DESCRIPTION OF THE DRAWING A typical and exemplary form ofembodiment of the device constituting the subject matter of thisinvention will now be described with reference to the attached drawings,in which:

LII

FIG. I is a cross-sectional view showing a printing cylinder providedwith a mounting and tensioning device for negative plate or sheetaccording to this invention, this section being taken along the line Hof FIG. 2;

FIG. 2 is a fragmentary plan view from above of the printing cylinder ofFIG. 1;

FIG. 3 is a fragmentary axial section taken along the line III-III ofFIG. 1;

FIG. 4 is a cross section taken along the line lV-IV of FIG.

FIG. 5 is a longitudinal section taken along the line V-V of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT The printing cylinderillustrated in the drawings comprises a peripheral wall 1 secured ateither end to transverse flanges 2 by means of screws 3. Each flange 2has an inner extension in the form of a cylindrical hub 4 and isrotatably solid with a shaft 5.

The cross-sectional contour of the peripheral wall I of this printingcylinder is not completely circular and has an angular amplitude ofabout 290. The longitudinal edges Ia and lb of this peripheral wall 1will thus define therebetween an aperture extending longitudinallythroughout the cylinder length between said flanges 2, and thetransverse are covered by this aperture constitutes a gap of about 70.However, this numerical value should not be construed as limiting theinvention, as will be seen presently.

A cylindrical tensioning sector 8 and a cylindrical bearing sector 9 areadapted to be mounted in the aperture defined by the longitudinal edgesla and 1b. The cross-sectional amplitude of these cylindrical sectors 8and 9 is about 32 for each sector, but again this value should not beregarded as limiting the scope of the invention.

The cylindrical tensioning sector 8 is rigid, at either end, with aradial arm ll formed with an integral sleeve 12 rotatably mounted on thehub 4 of flange 2. Besides, the cylindrical tensioning sector 8comprises at either end a radially thinner annular portion I3 of sameangular amplitude which fits on the peripheral surface 20 of flange 2.This portion I3 comprises a slot 14 extending transversely to andregistering with a tapped hole 15 formed in the peripheral outer surface2a of flange 2. A set screw 16 extending through said slot I4 is screwedin said tapped hole 15 for locking the cylindrical tensioning sector 8in the desired adjustment position on said flange 2.

The negative plate or sheet 17, illustrated in its operative andtensioned condition on the printing cylinder, has anchoring ends oredges l7a,I7b bent twice at right angles. As clearly shown in FIGS. 1and 4, the edges 17a and 17b engage the longitudinal gap 18 (having awidth a when the plate 17 is secured and tensioned) formed between thelongitudinal edge 8a of the tensioning sector and the longitudinal edgela of the peripheral wall 1. The ends or edges 17a and 17b are benttwice at right angles in order to provide an inner lip adapted to anchorthe negative plate I7 to the registering edges of sector 8 and wall 1.

The negative plate or sheet I7 disposed or wound on the printingcylinder is tensioned by means ofa screw [9 provided at each cylinderend and engaged in a support 21 rigid with the adjacent flange 2, alocknut being associated with this screw for maintaining the plate 17 inthe desired tensioned condition.

Notches 23 and 24 are formed in the bearing sector 9 and in thelongitudinal edge lb of the peripheral wall I of the printing cylinder,respectively, so as to register with the head of screw 19 and locknut 22and permit the tightening or loosening of these members from outside thecylinder.

The cylindrical hearing sector 9 comprises two longitudinal edges 9a and9b forming, in conjunction with the longitudinal edge 8b of tensioningsector 8 and the longitudinal edge lb of wall I, longitudinal gaps 25and 26 having widths denoted b and c respectively (assuming the negativeplate 17 is secured and tensioned).

The cylindrical bearing sector 9 comprises at either end an extension 27radially thinner than, but of same angular amplitude as, the remainingportion of the sector. This extension 27 has formed therethrough anelongated hole 28 having its major dimension disposed circumferentiallyand registering with a tapped hole 29 formed in the peripheral surface2a of flange 2. This tapped hole 29 is engaged by a set screw forlocking the cylindrical bearing sector 9 in relation to said flange 2.

Now, the manner in which the device according to the invention isutilized for tensioning and anchoring a negative plate 17 on theprinting cylinder will be described. Firstly, the screws 16 and 31 arereleased for loosening these mutually shiftable tensioning and bearingsectors 8 and 9. Thus, these sectors 8 and 9 can now slide freely on theouter peripheral surface 2a of flanges 2 while being guided by thescrews 16 and 31 engaging a sufficient number of threads of tapped holesand 29, respectively. Then, the bearing sector 9 is shifted in thecounterclockwise direction as shown in FIG. 1 so that its edge 9b willabut against the edge lb of peripheral wall 1. The same operation isrepeated with the other or tensioning sector 8, so that its edge 8b willabut against the edge 9a of sector 9. Under these conditions, the widthsb and c of gaps 26 and are reduced to zero while the gap 18 between theedge 8a of sector 8 and the edge la of wall 1 has its maximum width, Le.the sum of the widths of the gaps obtaining when the negative plate 17is tensioned, [.e. a b c (corresponding to an arc ofabout 6 in theexample described herein).

Then the two bent edges 17a and 17b of plate 17 can easily be insertedinto the gap 18 so that they can anchor themselves to the sector andcylinder edges la and 80.

When the edges of the negative plate 17 have thus been engaged the screw[9 is clamped so as to cause the arm 11 to pivot in the clockwisedirection as shown in FIG. 1. As a result, the tensioning sector 8 ismoved away from sector 9 and tends to move the plate edge 17a towardsits opposite edge 17b, so as to slightly tension this plate 17.

Having thus obtained this plate prestress corresponding to an angularshift of about 2 of the tensioning sector, the hearing sector 9 isslightly shifted in turn in order to create a gap 26 having a w idth.c(corresponding to an arc of about 2).

After this operation the tensioning of the negative plate 17 iscompleted by further moving the tensioning sector 8 away from thebearing sector 9 (with an angular shift of about 2) so as to createtherebetween a gap 25 having a width b (corresponding to an arc of about2).

With the negative plate 17 thus definitely tensioned, the setscrew 19 islocked by means of its locknut nut 22. Thus, the gap 18 has a width areduced to an arc of about 2.

Finally, the bearing sector 9 is also locked on flange 2 by means ofscrews 31 and the printing cylinder is ready for use.

From the foregoing it will be seen that the widths ofgaps 18, 25 and 26(corresponding each to an arc of about 2) are extremely small, of theorder of 2 to 3 mm (.0") in practice, in the case ofa printing cylinderhaving an outer diameter of mm (7"); under these conditions thetensioning sector 8 and bearing sector 9 can be utilized efficiently forprinting labels, vignettes, illustrations, etc., separated by nonprintedareas or strips coincident with the above-defined gaps 25 and 26.

Although the above described form of embodiment com prises only onebearing sector 9 it is clear that if it is desired to further reduce thewidth of the residual gaps such as 25 and 26, the number of bearingsectors such as 9 may be increased so as to increase accordingly thenumber of gaps such as 25 and 26 and therefore reduce their width.

Of course, the form of embodiment of the invention described andillustrated herein should not be construed as limiting the presentinvention since many modifications and variations may be brought theretowithout departing from the spirit and scope of the invention as setforth in the appended claims.

I claim:

1. A device for mounting a negative plate on the printing cylinder of arotary printing machine which comprises a shaft, a pair of lateralflanges rigid with said shaft and an outer peripheral wall discontinuedin order to provide a longitudinal aperture extending throughout thecylinder length, said device comprising a cylindrical plate-tensioningsector fitting in said cylinder aperture, and forming with its outerperipheral surface the partial continuation of the cylinder saidtensioning sector having anchored to one of its longitudinal edges onebent longitudinal end of said negative plate of which the other bent endis anchored to the registering edge of the peripheral surface of saidcylinder which bounds said cylinder aperture, a tensioning sectorsupport rotatably mounted on said cylinder shaft, means for adjustingthe angular position of said tensioning sector support in relation tosaid cylinder, to permit the control of the tension of said negativeplate, and at least one cylindrical hearing sector adjacent to saidtensioning sector, also fitting in said longitudinal cylinder apertureand forming with its outer periphery the continuation of the outersurface of said tensioning sector and of said cylinder, said cylindricalbearing sector being mounted for transverse adjustment on said pair oflateral flanges of said cylinder.

2. A device as set forth in claim 1, which comprises a pair of radialarms rotatably mounted about said cylinder shaft and rigid with saidcylindrical tensioning sector at either end thereof, a support rigidwith each lateral flange of said cylinder, and a screw engaging each oneof said support rigid with each lateralflange and bearing against aregistering radial arm.

3. A device as set forth in claim 1, wherein the tensioning and bearingsector comprises at each longitudinal end radially thinner portionsadapted to slip on the peripheral surface of the lateral flanges of saidcylinder, elongated holes formed in said thinner portions and set screwsextending through said elongated holes and engaging registering tappedholes formed in the peripheral surface of said lateral flanges.

